04 Silverado oil pressure

[steveo2155]

Looking at buying a 04 Silverado 1500 4x4 ext cab with 140000 miles from private party for $2500. Body is in good shape for the year. Runs and drives good. Oil pressure is at about 20 psi at idle and 40 to 45 psi when driving. Owner also said burns about 2 quarts of oil between oil changes. Is the oil pressure about normal or low? Just debating on even if worst case scenario, the engine needed replaced down the road beings its a cheap truck in good shape if it'd still be worth it? Approx cost for engine rebuild or finding a used 5.3 and paying some one to swap?

[Jworks]

Fair price for an '04 in my opinion.  I have a '11, 5.3.  My psi is 40 driving, and varies between 22 and 30 at idle.  I had an issue with psi a few months back.  It was 21 at any speed.  I was alarmed.  Shortly afterwards the engine light came on, coded check oil sensor.  I had that changed.  PSI went to 30 at highway speed.  Still 22 idling.  Someone told me to change oil and filter.  That didn't make sense to me, but I'm no pro.  So, I did.  I did it myself, higher end Fram synthetic oil filter and Mobil 1 oil.   Bingo.  Highways psi 40, idling 30, sometimes still 22.  But most of the time 30 at idle.  A mechanic on this website told me its the oil filter, he'd seen lots of them come back, and they were always the cheaper lower end filter, and I should insist on the higher end filter if I do oil changes at the dealer again.  I doubt the Mobil 1 had anything to do with the better psi.  I had been using Dexos at the dealer.  But the better filter, I think, was the reason.  Now I have a decision to make next oil change.  Do again myself or let dealer do it with the higher end filter.  I'd be more concerned about the 2 quarts between changes if I was you.  Thats saying something.  Hopefully a mechanic will respond to you.  Richard Wysong is a regular on here; I've read a lot of his posts and he's usually really good.  Maybe he can help you.

 

[CamGTP]

Perfectly normal oil pressure.

 

For the oil consumption I'd be trying a few things before going as far as replacing major parts of the engine. I'd replace a quart of oil with transmission fluid to help clean the insides of the engine or I'd try using Liqui Moly engine flush to help breakdown deposits.

 

Even if either doesn't help you could try different brands and weights of oil. 5W30 is just a suggestion, a 10W40 could be ran no problem. And if in reality the $10 in oil it uses between oil changes is super cheap compared to a different engine.

[richard wysong]

Thank you Jworks, Yeah that's a great price for a solid truck. I paid 2600 for my 04 C2500 WT, 6.0 this spring. my op is similar and well within specs so I wouldn't be too concerned with that, as J said an oil change may bring it up. It sounds like the owner was good with the maintenance. If it's burning the oil and not leaking it the problem is probably the PCV system. There was a post a couple months ago by 1 of the regulars here that cured it and I think it had the part numbers of the updated parts needed. Hopefully they see this and chime in or you can search the archives. I like my truck it's actually quieter than my Caddy but the frame rust is scary looking. they may have had a TSB for frame rust, slide under and take a look before you buy it or put it up on a lift end give it all the once over

[dsr611]

If you're worried about the oil pressure, you could drop the pan, pull the pickup tube and replace the o-ring.  Our 05 Tahoe had low oil pressure (low enough that it triggered the low oil pressure warning on the DIC).  I replaced the o-ring and pressure is now up over 40 and is no longer ticking like it was.